Ventilation phenotypes specific considerations

20 views 0 05/05/2020 and

  1. Mechanical ventilation strategy to COVID-19 is the one typically applied to severe ARDS: low tidal volume ventilation1
  2. Some patients with COVID-19 pneumonia and «ARDS» present with an atypical form of the syndrome described by a high lung compliance
  3. A conceptual model, based on respiratory physiology, leads to the development of a time-related disease spectrum within two primary phenotypes: Type L and Type H
    • Type L: Low elastance (i.e., high compliance), Low ventilation to perfusion ratio, Low lung weight and Low recruitability
    • Type H (20-30%; fits ARDS criteria): High elastance, High right-to-left shunt, High lung weight and High recruitability.
  1. Proposed respiratory treatment model based on the conceptual model:
    • Reverse hypoxemia through an increase in FiO2 with Type L patients
    • In type L patients with dyspnea, try non-invasive options such as high flow nasal cannula (HFNC), continuous positive airway pressure (CPAP) or non invasive ventilation (NIV)
    • Monitoring of inspiratory esophageal pressure swings should be considered and could be used to guide when to intubate sooner (above 15 cmH2O)
    • Once intubated and deeply sedated, the Type L patients can be ventilated with volumes greater than 6 ml/kg (up to 8-9 ml/kg). Prone position only as a rescue maneuver (modest benefit), and PEEP reduction to 8-10 cmH2O. An early intubation may avert the transition to Type H phenotype
    • Type H patients should be treated as severe ARDS (higher PEEP, prone positioning and extracorporeal support)

 

This subject is based on two editorials of Dr Luciano Gattinoni who question whether standard respiratory therapy protocols for ARDS are the best approach for COVID-19 pneumonia

Sources:

  1. Phua J., Weng L., Ling L., et al. (April 6 2020). Intensive care management of coronavirus disease 2019 (COVID-19): challenges and recommendations. Lancet. https://doi.org/10.1016/S2213-2600(20)30161-2
  2. Gattinoni L., Coppola S., Cressoni M., et al. (March 30 2020). Covid-19 Does Not Lead to a “Typical” Acute Respiratory Distress Syndrome. American Journal of Respiratory and Critical Care Medicine. https://doi.org/10.1164/rccm.202003-0817LE
  3. Gattinoni L., Chiumello D., Caironi P., et al (2020). COVID-19 pneumonia: different respiratory treatment for different phenotypes? Intensive Care Medicine; https://doi.org/10.1007/s00134-020-06033-2
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